1. Statement of the Technical Field
The invention concerns filtration equipment, specifically, filter bags used for such acts as removing organic contaminants, color, odor, or even chlorination from fluids.
2. Description of the Related Art
A filter typically consists of a cartridge or a bag for use in a pressurized filter system. A pressurized filter system utilizing filter bags is typically comprised of a filter housing having a body and a cover. The body contains a filter basket for placing the filter bag therein. The filter housing is comprised of a mounting stand, an input orifice, and an output orifice. A contaminated fluid is pumped into the filter housing through the input orifice. The contaminated fluid is filtered as it flows through the filter bag and then exists through the output orifice. Such a pressurized filter system is disclosed in U.S. Pat. No. 5,246,581.
A filter bag is typically composed of one or more layers of filtering medium. The filtering medium is typically made of a micro-fiber material having pores to control fluid flow. The layers of filtering medium can have a uniform pore structure, a graded pore structure, or a tapered pore structure. A tapered or graded pore structure provides a filtering material whereby the pore size decreases in the direction of fluid flow, i.e. from the input orifice to the output orifice. A multi-layer filter structure provides a filtering system able to collect contaminants at each layer of filtering medium.
Filter bags having a multi-layer filter structure typically become ineffective when contaminants are primarily collected at one layer. When contaminants are primarily collected at one layer, an inefficient fluid distribution over the filtering medium results. Also contributing to inefficiency is the decrease in the fluid flow rate through the filter bag. In such a situation, the filter bags life span is shortened.
Despite the various configurations known in the art there remains a need for a filter bag design which increases the efficiency of the filter material. A filter bag design is also needed which optimally enhances fluid flow while providing an extended life span.